Is this commercial transaction considered unlawful (haram), where the wallet is pre-charged with the producing company, payment is made by the customer via PayPal, then the company withdraws the amount from the wallet and sends the product to the customer, bearing in mind that funds are only withdrawn from PayPal at the end of the month?

The ruling is based on knowing the nature of the transaction between you and the buyer:

1. Agency on behalf of the owner: If you are an agent on behalf of the owner of the commodity, and they have authorized you to sell it at a known price, allowing you to increase the price for your own benefit, there is no harm in that. The electronic bank retaining the price until the end of the month does not affect this. 2. Salam (forward contract): If there was no prior agreement with the owner, and you agreed with the buyer on a described commodity to be delivered at a known future date, then the price must be paid to you at the time of the contract (either actually or constructively). The transfer of the amount to your electronic bank account is considered constructive possession, and the inability to withdraw it until the end of the month does not affect this. 3. Agency on behalf of the buyer: If you inform the buyer that you do not own the commodity and will procure it for them from its owner at a specific price, and they authorize you to do so, there is no harm in this agency.